No offense intended but I'm chuckling inside at your use of the word string.
Now, to your question.
You do want any wood to be dried. It will crack if its not dried.
HOW to ensure it's dried is another question. It takes about 1 year per inch of board thickness to air dry wood. (as long as air is able to circulate freely between the boards.)
I don't want to wait a year or years for pen blanks. I have often taken wet wood, drill a hole in the blank I've cut to appropriate size and let it air dry for several days. The walls will be much thinner and air can circulate from the inside and outside.
After several days, I redrill/ream out with a hand drill. The wood will probably have moved while drying. Then I glue in the tubes.
I turn the wood so it's proud of the bushings and let it sit a couple more days. Still acclimatizing (in my mind.)
Shortens the process considerably.
This is also part of the process I use for creating pens from ebony and snakewood. (woods prone to cracking)
I have never had to have any blank professionally stabilized. That's what thin ca is for.
drizzle - cut, drizzle - cut, repeat as necessary. CA and sharp tools.
I love Siberian Pea Shrub. I would go cut a piece, bring it to my shop, cut it to blank size and have a pen out of it in 10 days or so.
You can also dry the blank by microwaving it. (buy one at a thrift shop. DO NOT USE YOUR WIFES!) Run it 30 seconds followed by 10 minutes of resting. Repeat until it stops losing weight. Cut and drill.